Beat the eggs, 125 g sugar and salt with the whisk of the hand mixer until thick and creamy. Mix flour, almonds, starch and baking powder and stir in alternately with the milk. Place the dough on a greased pan of the oven (32 x 39 cm) lined with baking paper and smooth it down. Bake in the preheated oven (electric oven: 225 °C/ convection oven: not suitable/ gas: level 4) for 7-8 minutes. Remove the sponge cake from the oven and turn it over onto a damp tea towel sprinkled with 2 tablespoons of sugar and remove the baking paper immediately. Let the sponge cake cool down.
In the meantime soak the gelatine. Clean, wash and cut the rhubarb into bite-sized pieces. Bring orange juice, 75 g sugar and vanillin sugar to the boil. Add the rhubarb, cover and simmer at medium heat for about 5 minutes. Drain the rhubarb and collect the stock. Squeeze the gelatine and dissolve in 150 ml of the stock. Let cool down. In the meantime. Mix mascarpone, vanilla quark, icing sugar and orange peel. Stir the mixed gelatine drop by drop into the mascarpone mixture. Carefully fold in rhubarb, except for 2 tablespoons for decoration. Halve the sponge cake from the long side.
Let cool down. In the meantime. Mix mascarpone, vanilla quark, icing sugar and orange peel. Stir the mixed gelatine drop by drop into the mascarpone mixture. Carefully fold in rhubarb, except for 2 tablespoons for decoration. Halve the sponge cake from the long side. Cover one half with a baking frame. Put 2/3 of the mixture on top and smooth it down. Place the second base on top and spread the rest of the cream on top. Chill for at least 2 hours. Cut the cake into 12 pieces. Decorate with the remaining rhubarb and pistachios
Cover one half with a baking frame. Put 2/3 of the mixture on top and smooth it down. Place the second base on top and spread the rest of the cream on top. Chill for at least 2 hours. Cut the cake into 12 pieces. Decorate with the remaining rhubarb and pistachios